Bone marrow stem cells are endowed with in vitro multi-lineage differentiation abilities, and constitute an attractive autologous source of material for cell therapy. With regards to recent findings, adult mesenchymal stem cells (MSC) are commonly assimilated to neural crest stem cells (NCSC), both isolated from adult bone marrow. The objective of this study was therefore to highlight significant differences for membrane markers between those two cell types. Using the minimal criteria for defining multipotent mesenchymal stromal cells as previously described by The International Society for Cellular Therapy, we were quite surprised that no significant difference could discriminate MSC from NCSC. To define new markers, we first performed a microarray comparison. Based on those results, we validated selected targets by RT-PCR, then by immunocytochemistry. In parallel, we observed that NCSC had the unique property (compared to MSC) to grow as spheres, which could also be used as a purification protocol for NCSC from adult bone marrow. Altogether, we demonstrated that P75NTR was the most significant discriminating marker between MSC and NCSC, isolated from mouse adult bone marrow, which could be used as selecting marker in an enrichment protocol. Sphere formation could then be used as a purification protocol for NCSC. [less ▲]

in International Journal of Cancer = Journal International du Cancer (2015)

Osteopontin (OPN) is a secreted protein involved in most aspects of tumor progression and metastasis development. Elevated OPN expression has been reported in multiple types of cancer including ... [more ▼]

Osteopontin (OPN) is a secreted protein involved in most aspects of tumor progression and metastasis development. Elevated OPN expression has been reported in multiple types of cancer including glioblastoma (GBM), the highest grade and most aggressive brain tumor. GBMs contain a subpopulation of glioma-initiating cells (GICs) implicated in progression, therapeutic resistance and recurrence. We have previously demonstrated that OPN silencing inhibited GBM cell growth in vitro and in vivo. Moreover, activation of CD44 signaling upon OPN ligation has been recently implicated in the acquisition of a stem cell phenotype by GBM cells. The present study is aimed to explore OPN autocrine function using shRNA silencing strategy in GICs enriched from GBM cell lines and a human primary GBM grown in EGF and bFGF defined medium. The removal of these growth factors and addition of serum induced a significant loss of OPN expression in GICs. We showed that OPN-silenced GICs were unable to grow as spheres and this capacity was restored by exogenous OPN. Importantly, the expression of Sox2, Oct3/4 and Nanog, key stemness transcription factors, was significantly decreased in GICs upon OPN targeting. We identified Akt/mTOR/p70S6K as the main signaling pathway triggered following OPN-mediated EGFR activation in GICs. Finally, in an orthotopic xenograft mouse model, the tumorigenic potential of U87-MG sphere cells was completely abrogated upon OPN silencing. Our demonstration of endogenous OPN major regulatory effects on GICs stemness phenotype and tumorigenicity implies a greater role than anticipated for OPN in GBM pathogenesis from initiation and progression to probable recurrence. [less ▲]

Spinal cord injury (SCI) treatment represents a critical issue in clinical research and patient care. Stem cell-based replacement therapies have already been proposed worldwide, especially studying stem cells from the adult bone marrow stroma. Previous studies focusing on those cells did not specifically consider their intrinsic embryonic heterogeneity, thus intermingling different stem cells subpopulations to treat experimental SCI or even injured patients. In this study, we decided to compare adult bone marrow neural crest-derived stem cells (NCSC) and mesenchymal stem cells (MSC), and highlight which of their specific properties could be relevant in therapeutic perspectives. In that purpose, we compared NCSC and MSC isolated from adult mouse bone marrow. We then compared the effects that both cell types could exert once grafted inside an injured spinal cord. Cells were injected into the spinal cord of mice that right after a spinal cord contusion at the T11-12 spinal level. Our results indicate that both MSC and NCSC-injected mice recovered locomotion abilities faster than control mice (as assessed by BMS scoring). Additionally, we observed that after 28 days post-injury, the lesion volume tended to decrease in mice that received cell graft compared to control group. Interestingly, it appeared that MSC seemed to be able to modulate inflammation inside the lesion, more than NCSC. Indeed, MSC-graft increased early neutrophil and macrophage recruitment in the bloodstream and inside the spinal cord, and increased the number of arginase-1-expressing cells remaining in the spinal cord after 28 days. In parallel, we compared the secretome of both NCSC and MSC, and noticed some interesting differences: MSC secreted several chemokines reflecting possible immunomodulating properties, while NCSC secreted products might be able to enhance neurite outgrowth. Indeed, preliminary data showed that NCSC induced neuritogenesis on primary neurons in vitro. Altogether, those results should help to improve and optimize cell-based therapies parameters and/or to define precise and efficient pharmacological treatments for SCI patients. [less ▲]

Despite notable achievements in glioblastoma diagnosis and treatment, the prognosis of glioblastoma patients remains poor and reflects the failure of current therapeutic modalities. In this context ... [more ▼]

Despite notable achievements in glioblastoma diagnosis and treatment, the prognosis of glioblastoma patients remains poor and reflects the failure of current therapeutic modalities. In this context, innovative therapeutic strategies have recently been developed to specifically target glioblastoma stem cells, a subpopulation of tumor cells involved in experimental tumorigenesis and known to be critical for tumor recurrence and therapeutic resistance. The current review summarizes the different trails which make glioblastoma stem cells resistant to treatments, mainly focusing on radio-, chemo- and immunotherapy. This broad overview might actually help to set up new bases for glioblastoma therapy in order to better fight tumor relapses and to improve the patients’ prognosis. [less ▲]

Objectives: Spinal cord injury (SCI) treatment represents a critical issue in clinical research and patient care. Stem cell-based replacement therapies have already been proposed worldwide, especially studying stem cells from the adult bone marrow stroma. Previous studies focusing on those cells did not specifically consider their intrinsic embryonic heterogeneity, thus intermingling different stem cells subpopulations to treat experimental SCI or even injured patients. In this study, we decided to compare adult bone marrow neural crest-derived stem cells (NCSC) and mesenchymal stem cells (MSC), and highlight which of their specific properties could be relevant in therapeutic perspectives. Material and methods: In that purpose, we compared NCSC and MSC isolated from adult mouse bone marrow. We then compared the effects that both cell types could exert once grafted inside an injured spinal cord. Cells were injected into the spinal cord of mice that right after a spinal cord contusion at the T11-12 spinal level. Results: Both MSC and NCSC-injected mice recovered locomotion abilities faster than control mice (as assessed by BMS scoring). Additionally, we observed that after 28 days post-injury, the lesion volume tended to decrease in mice that received cell graft compared to control group. Interestingly, it appeared that MSC seemed to be able to modulate inflammation inside the lesion, more than NCSC. Indeed, MSC-graft increased early neutrophil and macrophage recruitment in the bloodstream and inside the spinal cord, and increased the number of arginase-1-expressing cells remaining in the spinal cord after 28 days. In parallel, we compared the secretome of both NCSC and MSC, and noticed some interesting differences: MSC secreted several chemokines reflecting possible immunomodulating properties, while NCSC secreted products might be able to enhance neurite outgrowth. Conclusions: Preliminary data showed that NCSC induced neuritogenesis on primary neurons in vitro. Altogether, those results should help to improve and optimize cell-based therapies parameters and/or to define precise and efficient pharmacological treatments for SCI patients. [less ▲]

Spinal cord injuries remain a critical issue in experimental and clinical research nowadays, and it is now well accepted that the immune response and subsequent inflammatory reactions are of significant ... [more ▼]

Spinal cord injuries remain a critical issue in experimental and clinical research nowadays, and it is now well accepted that the immune response and subsequent inflammatory reactions are of significant importance in regulating the damage/repair balance after injury. The role of macrophages in such nervous system lesions now becomes clearer and their contribution in the wound healing process has been largely described in the last few years. Conversely, the contribution of neutrophils has traditionally been considered as detrimental and unfavorable to proper tissue regeneration, even if there are very few studies available on their precise impact in spinal cord lesions. Indeed, recent data show that neutrophils are required for promoting functional recovery after spinal cord trauma. In this review, we gathered recent evidence concerning the role of neutrophils in spinal cord injuries but also in some other neurological diseases, highlighting the need for further understanding the different mechanisms involved in spinal cord injury and repair. [less ▲]

Introduction The molecular adaptations specifically induced by different muscle contraction types have only been partially elucidated. We previously demonstrated that eccentric contractions in human ... [more ▼]

Introduction The molecular adaptations specifically induced by different muscle contraction types have only been partially elucidated. We previously demonstrated that eccentric contractions in human quadriceps elicited proteome modifications that suggest a muscle fiber typology adaptation (Hody et al. 2011). We address this question in a more systematic way by examining the effects of different running modes on the mouse muscle proteome and the muscle fiber typology on the whole quadriceps. Methods Male adult mice (C57BL6) were randomly divided into downhill running (DHR, quadricipital eccentrically biased contractions), uphill running (UHR, quadricipital concentrically biased contractions) and untrained control (CONT) groups. Running groups performed five training sessions on an inclined treadmill for 75 to 135 min/day and the quadriceps muscles were dissected 96 hours after the last session. Muscle protein extracts of DHR and UHR groups (n=4/group) were subjected to a 2D-DIGE analysis coupled with mass spectrometry. The assessment of fiber type, size and number was performed on the rectus femoris of the three groups (n=6/group) using myosin heavy chain (MHC) immunofluorescence. Results In the proteomic analysis, eight spots identified as the fast MHC isoforms exhibited a lower abundance in DHR compared to UHR (p<0.05, t-test). In contrast, ATP synthase subunit a and tubulin ß were more expressed in DHR (p<0.05). Immunohistological analysis revealed a significant higher proportion of type I and IIa fibers for DHR compared to UHR or CONT groups (p<0.05, one-way ANOVA). Discussion Our data demonstrate that the eccentrically biased contractions in mice induced specific adaptations in protein expression as well as in muscle fiber type and size which may reflect a more oxidative muscle phenotype. The differences in stress placed on the muscle between both trainings may be responsible for some unique adaptations resulting from the eccentrically biased training. Eccentric training is known to protect skeletal muscles against exercise-induced muscle damage (EIMD) which may occur after intense eccentric contractions (Chen et al. 2010; Hody et al. 2011). It is also suggested that fast glycolytic muscle fibers are more vulnerable to EIMD than oxidative fibers (Lieber and Friden, 1988). Therefore, it would be interesting to investigate whether the molecular changes induced by an eccentrically biased training are involved in protection against EIMD. References Chen TC, Chen HL, Lin MJ, Wu CJ, Nosaka K. (2010). Med Sci Sports Exerc 42, 1004-1012. Hody S, Leprince P, Sergeant K, Renaut J, Croisier JL, Wang F, Rogister B. (2011). Med Sci Sports Exerc 43, 2281-2296. Lieber RL, Friden J. (1988). Acta Physiol Scand 133, 587-588. [less ▲]

Since several years, adult/perinatal mesenchymal and neural crest stem cells have been widely used to help experimental animal to recover from spinal cord injury. More interestingly, recent clinical ... [more ▼]

Since several years, adult/perinatal mesenchymal and neural crest stem cells have been widely used to help experimental animal to recover from spinal cord injury. More interestingly, recent clinical trials confirmed the beneficial effect of those stem cells, which improve functional score of patients suffering from such lesions. However, a complete understanding of the mechanisms of stem cell-induced recovery is seriously lacking. Indeed, spinal cord injuries gathered a wide range of biochemical and physiopathological events (such as inflammation, oxidative stress, axonal damage, demyelination, etc) and the genuine healing process after cell transplantation is not sufficiently defined. This review aims to sum up recent data about cell therapy in spinal cord lesions using mesenchymal or recently identified neural crest stem cells, by describing precisely which physiopathological parameter is affected and the exact processes underlying the observed changes. Overall, although significant advances are acknowledged, it seems that further deep mechanistic investigation is needed for the development of optimized and efficient cell-based therapy protocols. [less ▲]

BACKGROUND: Glioblastomas remain ominous tumors that almost invariably escape treatment. Connexins are a family of transmembrane, gap junction-forming proteins, some members of which were reported to act ... [more ▼]

BACKGROUND: Glioblastomas remain ominous tumors that almost invariably escape treatment. Connexins are a family of transmembrane, gap junction-forming proteins, some members of which were reported to act as tumor suppressors and to modulate cellular metabolism in response to cytotoxic stress. METHODS: We analyzed the copy number and expression of the connexin (Cx)30 gene gap junction beta-6 (GJB6), as well as of its protein immunoreactivity in several public and proprietary repositories of glioblastomas, and their influence on patient survival. We evaluated the effect of the expression of this gap junction protein on the growth, DNA repair and energy metabolism, and treatment resistance of these tumors. RESULTS: The GJB6 gene was deleted in 25.8% of 751 analyzed tumors and mutated in 15.8% of 158 tumors. Cx30 immunoreactivity was absent in 28.9% of 145 tumors. Restoration of Cx30 expression in human glioblastoma cells reduced their growth in vitro and as xenografts in the striatum of immunodeficient mice. Cx30 immunoreactivity was, however, found to adversely affect survival in 2 independent retrospective cohorts of glioblastoma patients. Cx30 was found in clonogenic assays to protect glioblastoma cells against radiation-induced mortality and to decrease radiation-induced DNA damage. This radioprotection correlated with a heat shock protein 90-dependent mitochondrial translocation of Cx30 following radiation and an improved ATP production following this genotoxic stress. CONCLUSION: These results underline the complex relationship between potential tumor suppressors and treatment resistance in glioblastomas and single out GJB6/Cx30 as a potential biomarker and target for therapeutic intervention in these tumors. [less ▲]

Spinal cord injured experimental animals are widely used for studying pathophysiological processes after central nervous system acute traumatic lesion and elaborating therapeutic solutions, some of them ... [more ▼]

Spinal cord injured experimental animals are widely used for studying pathophysiological processes after central nervous system acute traumatic lesion and elaborating therapeutic solutions, some of them based on stem cell transplantation. Here, we describe a protocol of spinal cord contusion in C57BL/6J mice, directly followed by bone marrow stromal stem cells transplantation. This model allows for the characterization of neuroprotective and neurorestorative abilities of these stem cells in a context of spinal cord trauma. [less ▲]

The curative and preventive efficiency of the isokinetic exercise, especially of the eccentric contraction, has been well demonstrated. However, intense or unusual eccentric exercise is known to induce ... [more ▼]

The curative and preventive efficiency of the isokinetic exercise, especially of the eccentric contraction, has been well demonstrated. However, intense or unusual eccentric exercise is known to induce muscle damage associated with delayed-onset muscle soreness (DOMS) and prolonged functional deficits. These negative consequences can frequently disturb the progress of re-education or training programmes. Since they can affect athletic performance and increase the risk of musculo-skeletal injuries, the structuro-functional alterations associated with DOMS may also be problematic in athletes. Therefore, to optimize the benefits of the eccentric work while avoiding muscle damage and occurrence of DOMS should represent a major objective for the practitioners. To date, the only systematic intervention that brings muscle protection against DOMS consists of performing repeated eccentric sessions at submaximal intensity. Besides its clinical use, isokinetic constitutes an interesting model to generate and investigate the DOMS phenomenon. The original association of eccentric injuring protocols with new emerging techniques of molecular biology appears to be a promising strategy to better understand the cellular and molecular mechanisms underlying exercise-induced muscle damage. Such data would provide better guidelines for prevention or treatment practice. [less ▲]

BACKGROUND: Patients with glioblastoma multiforme (GBM) have an overall median survival of 15 months. This catastrophic survival rate is the consequence of systematic relapses that could arise from ... [more ▼]

BACKGROUND: Patients with glioblastoma multiforme (GBM) have an overall median survival of 15 months. This catastrophic survival rate is the consequence of systematic relapses that could arise from remaining glioblastoma stem cells (GSCs) left behind after surgery. We previously demonstrated that GSCs are able to escape the tumor mass and specifically colonize the adult subventricular zones (SVZs) after transplantation. This specific localization, away from the initial injection site, therefore represents a high-quality model of a clinical obstacle to therapy and relapses because GSCs notably retain the ability to form secondary tumors. METHOD: In this work, we questioned the role of the CXCL12/CXCR4 signaling in the GSC-specific invasion of the SVZs. RESULTS: We demonstrated that both receptor and ligand are respectively expressed by different GBM cell populations and by the SVZ itself. In vitro migration bio-assays highlighted that human U87MG GSCs isolated from the SVZs (U87MG-SVZ) display stronger migratory abilities in response to recombinant CXCL12 and/or SVZ-conditioned medium (SVZ-CM) compared with cancer cells isolated from the tumor mass (U87MG-TM). Moreover, in vitro inhibition of the CXCR4 signaling significantly decreased the U87MG-SVZ cell migration in response to the SVZ-CM. Very interestingly, treating U87MG-xenografted mice with daily doses of AMD3100, a specific CXCR4 antagonist, prevented the specific invasion of the SVZ. Another in vivo experiment, using CXCR4-invalidated GBM cells, displayed similar results. CONCLUSION: Taken together, these data demonstrate the significant role of the CXCL12/CXCR4 signaling in this original model of brain cancer invasion. [less ▲]